I once skied a dazzling day with cheap sunglasses and spent the evening with gritty, weeping eyes that could not open to light. That was mild snow blindness, a UV burn on the cornea, and it taught me more about eye protection than any article. On bright Xinjiang snow the glare is sneaky because it does not hurt while it happens, and the bill arrives that night. The eye is the sensor you ski with; the burn is the bill; and the bill is paid in the dark, which is the one place you cannot ski, so the protection is the thing that keeps the mountain open to you.
I had treated sunglasses as a comfort item, like a neck warmer, and learned the hard way they are safety gear, like a helmet. The difference is the helmet saves you from the fall you see coming; the goggles save you from the glare you do not. The burn is silent on the hill and loud at night, and the loud night is the one that ends the trip, so the goggle is the quiet guard against the loud end, and the guard rides on your face, not in the bag where I used to keep it until the sun was already in my eyes.
Why snow is a mirror
Snow reflects up to 80 percent of UV, and at altitude the UV is already stronger. Your eyes take the bounce from below as well as above, so even a cloudy-bright day adds up. The goggle sun guide explains lens categories; the short version is that any goggle or sunglass you trust must block 100 percent of UVA and UVB, not just look dark. Dark glass without UV block is worse, because it dilates your pupil and lets more burn in, and I made exactly that mistake with the gas-station shades that looked fine and were not. The dark lens is the costume; the UV block is the guard; and the costume without the guard is the trap, because the eye opens wide to the very thing that hurts it, so the cheap shade is the dangerous one.
Goggles versus sunglasses
On the move I wear goggles; they seal and they take a fall. The lens selection guide covers tints, and for bright days a darker or polarised lens cuts the bounce. I keep sunglasses for the apres and the drive, with a strap so they do not slide. The cold-weather notes mention squinting as a cold habit; squinting also strains eyes already taking UV, so protect them and relax the face. A relaxed, goggled face is warmer and safer than a squinting, bare one squinting into the glare. The goggle seals the eye from the bounce; the sunglasses free the face off the snow; and the two have their places, but the snow is the goggle’s place, because the snow is the mirror that burns.
If it already hurts
Snow blindness shows up hours later: pain, light fear, a sand-in-eyes feel. The fix is out of light, cool cloth, no rubbing, and a clinic if it is bad. The snow safety tips all circle preparation, and this is the same: prevent, do not treat. I now treat a bright day like a cold day, gear up before I feel the need, because by the time the need shows, the damage is done and the evening is ruined. The resort safety page backs this up, and the cost of ignoring it is a night in the dark. The clinic is the last stop; the goggle is the first; and the first stop is the one that means you never reach the last, so the goggle is the whole cure, worn early and worn always on the bright snow.
The habit
Glasses on at the first glint, every lift, every flat light that still bounces. The snow safety tips repeat it because it is the one people skip. Protect the eyes like the skin; they do not forgive a skipped day, and a burned cornea is the fastest way to lose a trip you flew far for. I pack a spare pair of goggles now, because a lost or cracked lens on a bright week is the same as having none, and the mountain does not dim for your mistake. The eyes are the only ones you have on the snow; the goggle is the only thing between them and the mirror; and the mirror does not care, so the goggle must, worn from the first chair to the last, every bright day, without exception, because the exception is the one that burns.
A small add: on a bluebird day after fresh snow, the bounce is at its worst, and that is exactly the day people ski without goggles because the sky is so clear. The clear sky is the trap; the white ground is the mirror; and the mirror is the one doing the burning while you admire the sky. Goggle up on the clearest days, not just the flat ones, and the evening stays open instead of closed, and the trip stays on the snow instead of in the dark room.
The symptoms sneak up
Snow blindness is a sunburn of the eye, and like a sunburn it shows up hours after the damage. You ski a brilliant white day, the glare feels fine, and that night the eyes start to grit and water and hate the light. I have had the early version, a sandy ache that worsened in the dark, and learned to respect it before it became the full incapacity that keeps a skier in the lodge for a day. The danger is the pain-free afternoon; the snow reflects up to eighty percent of the UV, and the eye has no alarm for it until too late.
What to do if it hits
At the first grit, I stop, go indoors, and wear the darkest thing I have while the eyes rest. Cold compresses help, and so does doing nothing for a day, which is the hard part for a skier on a short trip. I carry a spare pair of plain dark glasses for the evening, because the pupils stay sensitive long after the slope is closed. The one time I pushed through, I lost the next morning to a throb I could have avoided by resting the night before, and the lost run was the expensive part, not the rest.
Choosing the right lens
For glare days I use a dark brown or black lens, not the rose I wear in flat light; the job is to cut the brightness, not to add contrast. A side shield matters more than people expect, because the UV comes from below off the snow and around the temple, not just the front. I keep two lenses and swap by the weather, and I never ski a whiteout-bright day in a light lens no matter how good the contrast feels. The sunglasses are the only thing between the eye and the reflected sun, and the skier who treats them as gear, not fashion, is the one who sees the next morning.
When to see a doctor
If the pain worsens after a night of rest, or the vision stays blurred into the next day, I go to the clinic rather than wait it out. The eye heals fast when treated early and sulks when ignored, and a ski trip is a poor place to gamble with sight. The cost of a visit is a few hours; the cost of a scarred cornea is a season, and the skier who books the appointment is the one who skis the spring.